Pump



June 17, 1941;

w. w. DAVIDSON I 2,246,276

PUMB v Filed Jan. 20. 1938 s sheets-sheet 1 June' 17, 1941. w.- DAVlDON ,2

' PUMP Filed Jan. 20. 1938 e Sheets-Sheet 2 6 Sheets-Sheet 3 June 17, 1941. w. w. DAVIDSON PUMP Filed Jan. 20, 1938 .Fune 17, 1941. w. w. DAVIDSON PUMP.

Filed Jan. 20, 1938 o Sheets-Sheet 4 6 Sheets-Sheet 5 June 17, 1941. w. w. DAVIDSON PUMP Filed Jan. 20, 1938 a R a V 1 v June 17,1941. w. w. DAVIDSON 2,246,276

PUMP

Filed Jan. 20, 1938 e Sheets-Sheet 6 Patented June 17, 1941 Application January 20, 1938, Serial No. 185,830

16 Claims.

A rotary pump, and for that matter any other type of a pump, to be commercially successful must meet certain rather well defined standards, and this is particularly true for moderate size refrigerant compressors, the market for which is highly competitive.

Generally speaking, these necessary attributes come under five headings, to-wit:

1. The pump must be able to pull a satisfactory vacuum when operating against either no head pressure or a head pressure corresponding to operating conditions.

2. The pump must meet certain requirements with respect to overall emciency, i. e. a pump of given displacement must stay within specified power limits when operating at various head pressures and, in the case of refrigerant compressors, the ratio of B. t. u. output to power input must stay within certain limits.

3. The pump must substantially maintain its overall efliciency under high temperature operating conditions, and it must be so constructed that after it has been run at the high temperatures for a considerable period of time, and then stopped,

it will be able to start again within a reasonable! period even though there are forces acting which .tend to oppose starting, such'as lower motor elliciency, smaller clearances between the relatively .movable pump parts, high head pressures, static friction, etc.' Furthermore, when the pump is started again under these conditions, the oil sealing and lubricating system should positively supply oil to the clearance spaces almost simultaneously with the starting of the pump, 'so that the pump will at all times have its desirable operating efliciency.

4. The pump should be so constructed that it is as nearly dynamically balanced as possible, and all relatively movable parts should be so arranged. and lubricated that the pump as a whole maintains its high efllciency and reliable performance over a long period of time.

5. The pump must have a minimum number of parts, all of which are easily machined and readily assembled.

The manner in which the pump of this invention achieves all of the above mentioned desirable check valve-for the discharge passage of the pump;

Fig. 3 is an enlarged exploded view of the principal pump members, ,all of which are shown in perspective;

qualities of a commercially-successful pump will become 'apparent as the disclosure proceeds and the description is read in conjunction with the- Fig. 4- is a horizontal sectional view looking down on the oil pump, the section being taken on the lines 4-4 of Figs. 1 and 5;

Fig. 4d is a transverse-sectional view through ,the lower pump bearing, the section being taken on the line la -4a of Fig. 5; 1

Fig. 5 is a vertical, sectional view taken on the line 5-5 of Fig; 4 and showingparticularly the sealing and. lubricating system, the remainder of the pump structure being' shown somewhat diagrammatically.

Fig. 6 is a transverse section through the upper pump bearing, the section being taken on the line 6-6 of Fig. 5;

Fig. 7 is a horizontal, sectional view through the inner assembly, the section being taken on the line of Fig. 5;

Figs. 8 andv 9 are horizontal, sectional views taken on the-lines 8-8 and 8-9, respectively, of Fi 5;

Fig. 10 is a fragmentary sectional view taken on the line Ill-l0 of Fig. 7;

Fig. 11 is a horizontal, sectional view showing a slightly different arrangement for the check valve on the discharge side of the pump;

Fig. 12 is a sectional view taken on the line I2-I2 of Fig. 11;

Fig. 13- is a fragmentary, vertical sectional view taken on the line |3-i3 of Fig. 4, showing the manner in which an oil cooling system may be incorporated into the pump;

Fig. 14 is a fragmentary bottom plan view of the oil cooling system; and

Figs. 15-18 inclusive are diagrammatic views illustrating the operation of the main pump E.

It should be understood that the description and illustration of what is now considered a preferred form of invention is merely for the purpose of complying with sec. 4888 of the Revised Statutes,-

and that the appended claims should be construed as broadly as the prior art will permit.

The pump of this invention, while it has many uses, is primarily intended as-a refrigerant compressor, and it peculiarly satisfles'all of the practical requirements for a commercial product.

General organization The pump in general comprises an outer casing or dome A within which the entire pump assembly is hermetically sealed. The inner assembly consists of a frame B having upper and lower bearings C and D, respectively, supporting a main pump unit E. This unit is driven through a shaft F by a standard electric motor G mounted above the pump E. The principal moving parts of the pump E are effectively-sealed against gas leakage as well as being lubricated by a sealing and lubricating system which includes an oil pump H operated from the lower end of the shaft F and submerged in an oil reservoir I at the bottom of the casing A.

The outer casing or dome The outer casing A consists of a base 26 which may either be cast, or stamped from a sheet of cold rolled steel of suitable thickness. In either case, the base preferably has a flange 2| to which a corresponding flange 22 of the dome'cover 23 is rigidly and hermetically sealed. The union may be made by bolting the dome cover to the base, as indicated at 24 (in which case a gasket 25 is preferably interposed between the flanges), or, if desired, the bolts and gasket may be omitted and the juncture of the two flanges may be welded. The base is supported on a plurality of feet 26, each of which preferably includes a resilient element, such as a rubber ball 21, for preventing vibration and sound from being transmitted from the casing to the part upon which the pump as a whole is supported.

On one side of the base 20, a small housing 28 is spot welded within which an intake check valve, generally designated 29, is located, the latter being mounted on a coupling member 30 and compris- 3| formed of spring steel and fixed at one end by screws 32 to the face 33 of the coupling member 30. The screws 32 also secure a spring retainer and stop 34 to the coupling member 30, the outer end being bent outwardly as shown in Fig. 4 and provided with a stud 35 to receive a spring 36 which bears against the flap valve 3| and tends to hold it in closed position. The stud 35, in addition to supporting the spring 36, limits the opening of the flap valve 3|.

To the opposed face 31 of the coupling member 30, a conventional compressor shut off valve 38 is secured by bolts 39 and the feed line to the a compressor includes a tube 40 leading to the shut off valve, a passageway 4| through the coupling member 30, and a copper tube 42 connecting the housing 28 with a recess 43 in a depressed portion of the base 20. Preferably, the tube 42 is silversoldered to the housing 28 and the base 20 in a manner well known to the art, to forms. gas tight seal.

On one side of the dome cover 23 a second compressor shut off valve 44 is mounted, and the discharge line from the compressor includes a tube 45 which communicates through the compressor shut off valve 44 with the interior of the dome through an opening 46. Preferably, the dome cover 23 is equipped with a. plurality of radially extending vertical fins 41 to assist in dissipating the heat from the dome.

Supporting frame for pump and motor The supporting frame B, for the main pump E, motor G and the oil pump'H is preferably a two part semi-steel casting consisting of a lower half and an upper half 5|. Since the lower bearing D for the pump E is carried by the lower casting 50, and the upper bearing C is carried by the upper casting 5|, it is important to provide means for securing the two parts of the frame B together in a predetermined angular relationship.

This is accomplished by providing mating flanges 52 and 53 on the upper and lower castings, respectively, the two flanges being held together by three or more screws 54, the heads of which are countersunk into the flanges 52 and have clearances 55 to permit the true angular alinement of the castings to be determined by two or more dowel pins 56 which have a tight press flt in one of the flanges 52 or 53, and a light press fit in the other. .The dowel pins are accurately located so that when the two castings are secured together, the bearings C and D which support the main pump E are in exact alinement.

The lower casting 50 has its lower face machined to rest upon a slightly raised machined portion of the base 20, and the casting is held in fixed relationship to the base by upstanding studs 51 welded into the base and having nuts 53 which clamp the casting 50 in place. To save weight and to provide for additional space for oil, portions of the side wall of the lower casting 50 are i cut away as indicated at 53, as best shown in Figs.

1 and 4.

The upper casting 5| of the frame B has an annular ledge 60 adapted to support the stator 6| of the motor G. The lower portion of the winding of the stator extends down into an annular trough 62 in the casting 5|, and the connecting wall 63 between the trough 62 and the flange 52 is preferably cut away at intervals as indicated at 64, to conserve weight. The stator 6| is held to the frame B by bolts 65 as shown in Figs. 1 and 5.

The main pump The main pump E is preferably of the rotating cylinder type in which two eccentrically mounted pump members rotate on their own centers in a manner to produce a pumping action.

In the embodiment of the invention shown, the pump comprises a cylinder ring 10 preferably made of semi-steel having an accurately machined inner cylindrical surface H, the ring being supported for rotation about an axis defined by the outer bearing surface of the bearings C and D by cylinder heads 12 and 13 which are clamped to the ring by elongated machine screws 14 having slight marginal clearances with the upper head I2 and the ring 10, in order that the angular position of the ring 10 with respect to thebearings C and D may be accurately determined by three or more dowels 15 extending between the ring 10 and two cylinder heads I2 and I3. The dowels have a tight press flt in the cylinder heads and a light press fit in the cylinder ring for convenience of manufacture and assembly.

Since the cylinder heads 12 and 13 are preferably made of semi-steel, it is desirable to drive hardened steel bushings 16 into the hubs of the heads to assure long life for the bearing surfaces.

Within the cylinder ring 10 is an eccentrically mounted rotor ll which is also preferably made of semi-steel, the rotor being keyed to the shaft F as indicated at '18 and having its outer surface drical surface ll ,of the ring 10. Y

Hardened steel end plates 63, 64 are fastened by screws 85 to the ends of the rotor and these plates are accurately machined to provide a close sliding fit with the correspondingly machined planar surfaces 86 flanking the ring ill. The plates bear. against the bearings C and D, but have slight clearances with the cylinder members I2 and I3 as best shown in Fig. 1.

The crescent-shaped space 90 between the ring Ill and rotor I1 is divided into intake and discharge sides by a vane generally designated 9i, preferably of hard steel, which has an enlarged portion 92 drive fitted into a recess 93 in the rotor TI.

into place.

The portion of the vane which projects beyond the rotor is carefully machined to have a close sliding fit in a slot 95 of a rocker 96, the latter being of cylindricalrform and rotatably mounted in the cylinder ring Ill. The vane may, therefore, be said to have a tight fit with respect to one of the pump members and a rocking and sliding engagement with the other member.

The vane has a gas tight fit with the end plates 83 and 86, and this fit is assured by small dowels 91 which are driven through the plates into the vane. If desired, the portion of the vane which projects from the rotor may, be made slightly wider and fitted within slots in the end plates in order to more perfectly efiect a gas tight seal between the vane and the end plates.

The fluid intake into the pump E includes in addition to the feed pipe Ml, tube 32 and recess d3, an axial passage 98 which communicates with a radial bore 98 in the shaft and another bore H m in the rotor which leads into the intake side of the pump chamber. The discharge passageway from the pump chamber includes a bore Hit in the enlarged portion 92 of the vane, the recess 93 and bore I02 in the rotor, a radial bore I03 in the shaft and an axial bore M4 in the shaft which extends upwardly and connects with the chamber I05 of a combination lock nut and oil separator, generally designated I06.

A check valve, generally designated IE1, is interposed in the discharge passageway, either at the base of the vane, as shown in Figs. 1 and 2 particularly, or preferably in a separately formed member or plug I08, as shown in Fig. 11. The valve in both cases consists of a flap I09 which is normally held on its seat by a leaf spring lit, the ends of the flap I09 and spring IIIi being secured in place by a screw III. When the check valve is located at the base of the vane, as shown in Figs. 1 and 2, a clearance space.ll2 is provided in the adjacent portion of the rotor to permit opening of the valve.

There is an advantage in placing the check valve Hill in a plug which is completely disassociated from the vane, as shown in Fig. 11. With this modification, the vane can be machined in a cross-sectionally rectangular shape of the simplest form. The discharge passage for the pump in this embodiment comprises two chordal bores in communication with each other through an intermediate longitudinal bore running parallel to the axis of the rotor. The remote ends of the chordal bores terminate, one upon the cylindrical surface 19 proximate the vane, and the other in a radial bore leading to the axial passageway IM. The plug I08 is driven into the longitudinal bore with the valve I01 opening inwardly away from the pump chamber 90.. The plug I08 is preferably tapered, as shown in Fig. 12, and the rear The vane is securely held in the rotor by taper pins 94 and Me which are driven tightly half of the plug is cut away to provide the necessary room for the check valve.

It will be understood that as the shaft F is rotated in the direction shown by the arrows in Figs. 15-18 inclusive, the vane SI sweeps through the crescent-shaped pump chamber and displaces fluid to effect a pumping action. Simultaneously, the intake side of the pump is drawing in additional fluid to be compressed on the next cycle of operation.

Motor drive The motor G which drives the shaft F is preferably a standard alternating current hermetic motor of the capacitor start, induction run type. The rotor H5 is mounted on a sleeve H6 which has an instanding flange II'I adapted to rest on a shoulder IIB of the shaft, so that the rotor is supported in appropriate relation to the stator GI. The motor rotor H5 is. clamped in place by the lock nut I06 which is screw-threaded onto the threaded end I I9 of the shaft and preferably, though not necessarily, a lock washer I20 is used to lock, the cap on the shaft.

The leads for the motor G are brought into the dome through gas tight terminals I3! (Fig. 4) of conventional make, the terminals preferably being located in the base 20 of the dome or outer casing.

. Sealing and lubricating system In order to have a highly efiicient pump, it is necessary to effectively lubricate the moving parts and seal them against gas leakage. In thepresent invention, this is accomplished by providing a positive displacement oil pump which forces the oil taken from a reservoir I through a series of passageways into the bearing surfaces and the various-clearance spaces where there is a gas pressure difierential which tends to cause gas leakage.

The oil pump is best shown in Figs. 1 and 4, and it comprises a rotor I2I which is mounted on an eccentrically formed reduced portion I22 of the shaft F. The rotor l2I travels in a planetary manner within a cylindrical recess I23 formed in the base of the lower casting 5|! of the supporting frame 15 and a vane I24 fixed by a dowel l 25 in the rotor I2! has sliding and rocking engagement with the casting 5B to divide the crescentshaped pump chamber I26 into intake and discharge stages. The sliding and rocking engagement of the vane with the casting 50 is accomplished by means of a cylindrical rocker I21 which is recessed into the base of the casting and has a slot in to receive the vane. The rear of the slot I28 communicates with the intake side of the oil pump by means of a small passage, shown in dotted lines in Figs. 1 and 4, so that oil cannot be trapped behind the vane as it reciprocates within the rocker I21.

The bottom of the pump chamber is closed by a plate I29 which is suitably secured to the casting, as by means of screws I30. Preferably the rotor iii, the vane I24, the rocker I21 and the end plate 829 are all made of hardened steel.

In the form of the invention shown in Fig.4, oil is taken from the reservoir or sump I through a screen I35,'tube I36 and bore I31 in the lower casting 50 in to the low pressure side I38 of the oil pump. The planetary movement of the rotor I2I forces the oil through a series of connecting passageways to the parts to be lubricated and The pump H being discharge passage I39 in the lower casting 50,

a tube I40 which connects the passage I39 with the bore MI in the upper casting bore I42 extending vertically through the bearing C and various branch bores and passageways, one of which. I43 communicates with a vertical g oove I44 to lubricate and seal the upper portion'of the shaft F and another bore I45 communicating with a verticalgroove I46 and an annular groove I41 to lubricate and seal the bearing which supports the upper cylinder head 12.

A diagonal bore I48 in the hub of the cylinder head 12 connects the grooves I46 and I41 with the interior of the cylinder head and thus constantly fills the space between the upper cylinder head 12 and the end plate 83 and ring with oil'under pressure. A circular groove I49 in the upper face of the ring 10 assures that the underside of the plate 83 is properly lubricated and sealed against gas leakage, and this circular groove communicates through a diagonal bore I50 with a recess I59 to supply oil under pressure to the rocker 96.

Thelower part of the pump E is lubricated and sealed by a series of passageways which include a portion of the discharge passageway I39, a diagonal bore I55 in the lower casting 50, a vertical bore I56 in the bearing D, and various branch passageways which communicate with this latter bore. One such passageway I51 connects the bore I56 with a vertical groove I58 which lubricates and seals the lower end of the shaft. An-

portioned for the displacement of the oil pump and the size of the storage passageways, the overall emciency of the pump may be maintained at a high standard and still have a quietly operating pump. The amount of oil to be discharged through the opening empirically for a pump of given size and proportions, but ,it is suificient for this disclosure to know that the relief passageway must be small enough to maintain the desired pressure in the oil system, and yet large enough to avoid setting up undesirable back pressure and causing the pump to operate noisily.

For the same purpose, the tube I is provided with arelief vent I61, the size of which is also empirically determined to suit conditions.

The cross sectional areas of the relief vents I66 and. I61 are more. or less complemen'tary, for their total cross sectional area determines the oil pressure in the lubricating and gas sealing system g Undei some circumstances, it may be desirable to provide an oil cooling system, and this may be conveniently done in the manner shown in Figs. 13 and 14. As there shown, oil is taken from the reservoir Land passed downwardly through a screen I10 into a spiral copper tubing coil I15 which is supported beneath the base 20 bya cupshaped brass or copper plate I12 which is soldered, or otherwise secured by a metal bond to the tubing I1I to assist in the heat dissipation,

and is preferably provided with perforations I13 ,to facilitate the circulation of air over the tubing.

A space I14 is left between the-top of the marglnal flange I15 around the plate I12 50 that air may freely circulate through the openings I13 over the tubing HI and out through the space other such passageway I59connects the bore I56 with a vertical groove I60 and an annular groove I65, both of which serve to lubricate and seal the lower supporting bearing for the lower cylinder head 13. A diagonal passageway I62 connects the annu-- the plate 04 is effectively lubricated and sealed against gas leakage, and this groove communicates with the rocker 96 through passageways I52 and Oil is permitted to flow freely into the rear portion of the slot 95 of the rocker 96 to lubricate and seal the vane SI, and to avoid setting up a damaging back pressure in the lubricating system, the slot 95 being in free communication with the space between the lower cylinder head 13 and adjacent end plate by means of a passage I66 which is cut through the upstanding flange of the lower cylinder head 13 (see Figs. 3 and 5).

To further avoid the possibility of creating undesirable back pressures in the lubricating and sealing system which would not only damage the overall efliciency of the pump, but also tend to' The coiled tubing I1I re-enters the dome through an opening I16 where it communicates with the intake passage I31. A plug I11 closes the passageway I31 to the space within the dome.

Assembly and accessibility of parts for repair and replacement In the manufacture of the pump and its assembly, the preferred routine is as follows: First the lower casting 50 with the oil pump H fitted into place is secured to the base 20 of the dome. The main pump E is then built up by taking the shaft F, keying the rotor 11 and the lower end plate 84 to the shaft with the vane 9| in place.

The cylinder ring 10 is then laid on the plate 84 with the vane engaging the rocker 96, and the top end plate 83 is then screwed into place (it .may here be noted that the projecting end plates of the shaft being slightly rounded, as indicated at I68 to facilitate this part of the assembly) and the top frame including the upper casting 5I and the stator is then clamped to the lower frame by the screws 54, the dowels 56 determining the proper angular relationship between the upper and lower frame. The rotor is then slipped over the top of the shaft and the oil separator and retaining nut I 08 is screwed into place.

I66 must be determined 'azaaavc From this brief explanation of the preferred method of assembly of the pump, it is obvious that when necessity demands, the casing may be opened and the motor readily replaced, or even the entire pump unit E may be removed for inspection and repair.

L Summary of advantages The following advantages are present in the pump structure which has been described and shown in the drawings:

1. The eccentric I22 on the shaft F may bear such angular relationship with the point of tanmain pump. In other words, if desired, the moment when the oil pump H delivers its maximum pressure during a given cycle of operation may be made to coincide with (or slightly precede) the moment when the main pump E develops its greatest pressure in the pump chamber, so that maximum sealage is obtained.

2. Centrifugal force aids in closing the check valve lll'i' .in the discharge passage of the pump.

3. By driving the inner pump member and arranging the vane 98 so that it has a rocki and sliding engagement with the outer cylindrical member, it is possible to construct a pump of given theoretical displacement with less material than if the outer member were driven and the vane had rocking and sliding engagement with the inner member.

4. Simplicity of pump structure is obtained by having the intake passage for the main pump extend axially through the shaftin one direction and the discharge passage extend axially through the shaft in the other direction.

5. By placing the oil pump below the oil level, the pump is always full of oil so that whenever the pump starts, it immediately begins to pump oil pump and thereby interfere with lubrication.

and sealing.

7. The main pump E can. be used as a rotary engine with little or no modification. This is in contradistinction to many prior art rotary engines which cannot be made to operate as pumps without radical reorganization.

Moreover, the particular combination of pump parts, their relationship to one another-all in combination with an efilcient lubricating and gas sealing system-constitute an important part of this invention, and failure to' describe any such combination or relationship of. parts, although shown in the drawings, should not be interpreted as revealing a lack. of appreciation of their importance or advantage. Although certain preferred embodiments of the invention have been shown and described herein, it will be apparent to those skilled inthe art that various and further uses, modifications and changes may be made without departing from the spirit and substance of the invention, the scope of which is commen surate with the appended claims.

I claim: 1

1. In a rotary pump or the like, pump members comprising a cylinder, a rotor mounted in the cylinder in eccentric tangential relation thereto, end walls rigidly secured to the rotor and having quiet ports respectively, said vane being rigidly flxed in one of the members and having rocking and sliding engagement with the other, bearing means for the cylinder extending laterally therefrom, bearing means for the rotor, and means for producing a pumping .action between the rotor and the cylinder.

2. In a rotary pump of the type having a crescent-shaped pump chamber, an outer pump member having an inner cylindrical surface flanked with planar surfaces normal, to the axis of the cylindrical surface, an inner pump member of cylindrical form mounted in eccentric tangential relation. to the inner surface of the first mentioned pump member, a vane extending between the two members dividing the pump chamber into intake and discharge stages having inlet and outlet ports respectively, said vane being rigidly fixed in one of the members and having rocking and sliding engagement with the other, end walls rigidly secured to the inner pump member having sealed engagement with the vane and sliding engagement with the planar surfaces of the outer pump member, bearing means for the outer pump member extending laterally therefrom, bearing means for the inner pump member, and means for producing a pumping action between the pump members.

3. In a rotary pump orthe like, pump members comprising a cylinder, a rotor mounted in the cylinder thereto, end walls rigidly secured to the rotor and having sliding engagement with the cylinder,

- a vane rigidly secured in sealed engagement to into intake and discharge sections having inlet and discharge ports respectively, and means for producing a. pumping action between the rotor and the cylinder.

- vane rigidly fixed relative to the end walls and discharge stages having inlet and outlet ports respectively, and means including the vane for positively rotating both the rotor and the cylinder to produce a pumping action between the rotor and the cylinder.

6. In a rotary pump of the typeincluding' an outer rotatable member having planar surfaces at its v ends, a cylindrical rotor eccentrically mounted in tangential relation to an inner cylindrical surface of the outer rotatable member, the

combination therewith of end walls rigidly fixed to the rotor and arranged for sliding engagement with the planar surfaces on the outer member, a vane rigidly fixed to the rotor having a tight fit with the end walls and having rocking in eccentric tangential relation and sliding engagement with the cylindrical surface, inlet and outlet ports upon opposite sides of the vane, and means for driving the rotor.

7. In a rotary pump of the class described, a sealed casing, a pump unit in the casing comprising an oil pump having a stationary outer cylinder, a gas pump having a. rotatable outer cylinder, and an electric motor rotor all rotatable on a common vertical axis with the latter two surmounting the oil pump, a quantity of oil in the casing sumcient to submerge the oil pump enough to render it promptly effective to deliver oil directly to the gas pump on starting but not sufficient to submerge a substantial part of the rotating cylinder of the gas pump, said gas pump including a rotor eccentrically mounted in tangential relation with the cylinder and having a vane extending between the rotor and the cylinder to divide the crescent-shaped space between the rotor and the cylinder into intake and discharge stages, means for driving the rotor of the gas pump from the electric motor rotor, and shaft means extending downwardly from said pump rotor to drive the oil pump, said oil pump being constructed and arranged to deliver oil to the gas pump at a pressure greater than the pressure in the casing.

8. For use in a pump of the class described, a rotor having separately formed but rigidly attached flanking end walls of greater diameter than the rotor itself, and a vane rigily secured to the rotor and the end walls and extending outwardly from the rotor.

9. In a rotary pump of the class described,

an outer pump member having an inner cylindrical surface flanked by planar end walls normal to the axis of the cylinder surface, cylinder support rotor and the outer pump member into intake and discharge chambers having inlet and discharge ports respectively, and a lubricating and gas sealing system associated with the pump including means for supplying oil under pressure to the space between the rotor end plates and the cylinder support heads whereby said space is constantly filled with oil under pressure.

10. In a rotary pump of the class described, an outer pump member having an inner cylindrical surface flanked by planar end walls normal to the axis of the cylinder surface, cylinder support heads attached to the outer pump member and having alined hub bearings, an inner pump member com prising a rotor mounted within the outer pump. member in eccentric tangential relation to the insliding engagement with said rocker in the outer pump member for dividing the crescent-shaped space between the rotor and the outer pump member into intake and discharge chambers having inlet and discharge ports respectively, and a lubricating and gas sealing system associated with the pump including means for supplying oil under pressure to the space between the rotor end plates and the adjacent cylinder support heads and to that, portion of the space behind the vane within said rocker whereby said spaces are constantly filled with oil under pressure, and a relatively large passageway connecting the two spaces.

11. In a rotary pump of the class described, an outer pump member having an inner cylindrical surface flanked by planar end walls normal tov the axis of the inner cylindrical surface, cylinder support heads attached to the outer member and ner cylindrical surface, means for driving at least i one of said pump members for producing a. pumping action between the rotor and the outer pump member, end plates rigidly attached to the rotor having sliding engagement with-the end walls of the outer pump member and being spaced from the adjacent inner faces of the cylinder support heads, a rocker mounted in the outer pump memhaving alined hub bearings, a rotor mounted within the outer member in eccentric tangential relation to the cylindrical surface having laterally extending trunnion bearings projecting through the cylinder support heads, end plates rigidly secured to the rotor and having sliding engagement with the planar end walls of the outer pump member to form a crescent-shaped pump chamber between the rotor and the outer member, a vane rigidly secured to the rotor and having rocking arid sliding engagement in the outer pump member to divide the pump chamber into intake and discharge sides having inlet and discharge ports respectively, bearing means for cooperating with the trunnion bearings of the rotor and the hub bearings of the cylinder support heads, and means for applying a driving force to the rotor to rotate the rotor and vane to produce a pumping action within the pumpchamber.

12. A pump comprising a shaft, a rotor secured to the shaft, a cylinder, laterally extending bearings supporting said shaft, and cylinder eccentrically to each other, with the rotor tangential to the cylinder, a vane and end walls rigidly carried by said rotor in mutually sealed relation, the end walls and the vane having a sliding engagement with the cylinder, inlet and outlet ports on opposite sides of the vane, and means carried by said shaft for driving the shaft, said shaft and rotor having a passageway interconnecting the pump compartment and an isolated compartment having a fluid therein.

13. In a rotary pump or the like, pump members comprising a cylinder, a piston mounted in the cylinder in eccentric tangential relation thereto, end walls rigidly secured to the piston and having infinitesimal clearances with the cylinder, a vane rigidly secured to one of the pump members, sliding in a rocker in the other pump member, and having sealing engagement with the end walls for dividing the work chamber between the pump members into intake and discharge sections, said sections havinginlet and outlet ports respectively, means for rotating the pump members for producing a pumping action between them, and an oil pump and conduits for delivering oil at a pressure higher than the pressure of discharge from the work chamber to the clearances between the end walls andthe cylinder and to the sliding surfaces of the vane and the rocker.

14. In a rotary pump hr the like, pump members comprising a cylinder, a piston mounted in the cylinder in eccentric tangential relationthereto,'-..

end walls rigidly secured to the'piston and having infinitesimal clearances with the cylinder, a. vane rigidly secured to one of the pump members, slidber, a vane fixed to the rotor and having a sealed ing in a rocker in the other pump member. and

groove extending substantially throughout the sure higher than the pressure of discharge from the work chamber to the clearances between the end walls and the cylinder and to the sliding surfaces of the vane and the rocker, including a groove extending substantially throughout the circumference of each of said clearance spaces approximately as close to the work chamber as the difference between the diameter of the piston and I the diameter of the cylinder.

15. In a rotary pump or the like, pump members comprising a cylinder, a piston mounted in the cylinder in eccentric tangential relation thereto, end walls rigidly secured to the piston and having infinitesimal clearances with the cylinder, a vane rigidly secured to one of the pump members, sliding in a rocker in the other pump member, and

having sealing engagement with the end walls for dividing the work chamber between the pump members into intake and discharge sections, said sections having inlet and outlet ports respectively, means for rotating the pump members for producing a pumping action between them, and an oil pump and conduits for delivering oil at a pressure higher than the pressure of discharge from the work chamber to the clearances between the end walls and the cylinder and to the sliding surfaces of the vane and the rocker, including a circumference of each of said clearance spaces approximately as close to the work chamber as the difference between the diameter of the piston and the diameter of the cylinder, said oil pump being positioned within a reservoir of oil below the oil level therein, and said cylinder being positioned above said oil level.

16. In a rotary pumpor the like, pump members comprising a cylinder, a piston mounted in the cylinder in eccentric tangential relation thereto, end walls rigidly secured to the piston and having infinitesimal clearances with the cylinder, a

vane rigidly secured to one of the pump members,

sliding in a rocker in the other pump member, and having sealing engagement with the end walls for dividing the work chamber between the pump members into intake and discharge sections, said sections having inlet and outlet ports respectively, means for rotating the pump members for producing a pumping action between them, bearings for the cylinder on both sides thereof, and cantpreventing bearing means for the piston, and an. oil pump and conduits for delivering oil at a pressure higher than the pressure of discharge from the work chamber to the clearances between the end walls and the cylinder and to the sliding 1 surfaces of the vane and the rocker, including a groove extending substantially throughout the circumference of each of said clearance spaces approximately as close to the work chamber as the difference between the diameter of the piston and the diameter of the cylinder.

' WILLIAM WARD DAVIDSON. 

